This invention relates generally to a grass edger or trimmer which employs a short length of plastic or the like cord as the grass cutting element and more particularly to an assembly for removably attaching the cord to a rotatably driven member of the trimmer.
Many different arrangements for attaching a length of cord to a rotatable member in a grass trimmer or edger are shown in the prior art. For example, in one embodiment shown in U.S. Pat. No. 3,708,967, issued Jan. 9, 1973, lengths of cutting line are looped through apertures spaced about the periphery of and tied to a rotatable disk. In an alternative embodiment of the device, radially extending apertures communicating with the peripheral apertures are also provided in the disk. Lengths of line, each having a knotted end, are received in the last mentioned apertures. The knots secure the lines to the disk with the aid of the centrifugal force produced during rotation thereof.
Still another arrangement for attaching short lengths of line to a rotating member in a grass trimmer is shown in U.S. Pat. No. 3,831,278, issued Aug. 27, 1974, wherein a diametrically extending channel is defined in the member. An axial recess communicating with the channel is also formed in the member. A knot or enlarged hub portion at the center of a length of cutting line is received in the recess with the opposite ends of the line extending radially outwardly through opposite ends of the channel. In this case, the central knot secures the line to the member against the centrifugal force created upon rotation of the member.
While the prior art arrangements described heretofore function satisfactorily for the most part to secure a length of cutting line to the rotating member of a grass edger or trimmer, they have certain disadvantages which make them undesirable. For instance, in the case of the first described embodiment of the U.S. Pat. No. 3,708,967 patent, tying the end of the cutting line to the rotating disk member can be time consuming as a typical nylon or plastic cutting element while being relatively flexible is sufficiently stiff to make it difficult to tie. The use of a knotted end on the cutting line to retain the line in position with respect to the rotating member provides no positive means for securing the line during non-use of the trimmer as it requires the centrifugal force generated by the rotating member to retain the line on the member.
In the case of the U.S. Pat. No. 3,831,278 device, it appears that mounting the cutting line properly on the rotating member could also be difficult and time consuming.
In addition to the above, it should be noted that in the prior art arrangements discussed, the cutting lines illustrated have had circular cross sections. The cutting surfaces therefore appear to be somewhat blunt and could thus be less effective against thick or high grass.